Stinging ants appear eradicated on Maui

Rapid response and the development of innovative pest control methods coordinated by the Hawai`i Department of Agriculture (HDOA) has resulted in eradication of an infestation of a highly invasive pest, called Little Fire Ants (LFA), on Maui. LFA, which delivers painful stings, were reported by a Maui farmer in October 2009 and were found to infest about a half acre of the farm in Waihee.

After LFA was detected one year ago, HDOA conducted an aggressive response to survey, contain and treat the infestation. HDOA obtained a special permit from the Environmental Protection Agency to use a special experimental ant bait developed by scientist, Cas Vanderwoude, with the Pacific Cooperative Studies Unit at the University of Hawaii at Manoa (PCSU). Until this new bait was developed, there were only ground treatments for LFA. The new bait provided treatment in trees and vegetation where LFA nest. The area had been treated monthly and by February of 2010, no LFA have been detected at that site. Monitoring will continue for at least another year.

“We have been routinely monitoring the area and we are confident that the ants have been eradicated on the property,” said Dr. Neil Reimer, manager of HDOA’s Plant Pest Control Branch. “It’s pretty clear that without the development of the experimental bait, we would not have been able to eradicate this pest so quickly, if at all.”

“The new pest control methods the state deployed were successful in part because the Little Fire Ants were detected early,” said Sandra Lee Kunimoto, Chairperson of the Hawai`i Board of Agriculture. “This incident serves as an example of why early detection is so important if we are to have any chance of eradicating a pest. We need everyone to be on the lookout for potentially invasive species and, most importantly, to report it to us as soon as possible so appropriate action may be taken to minimize the impact to Hawai`i’s agricultural sector and environment.”

HDOA, PCSU, the County of Maui, the Maui Invasive Species Committee (MISC) and the U.S. Geological Survey are working together to deliver public awareness programs and survey key risk areas on Maui for this ant. HDOA staff has also trained County of Maui employees, MISC and private pest control operators to assist in recognizing and reporting possible infestations on the island. MISC is also assisting HDOA in conducting surveys at high-risk areas on the island. So far, there have been no other detections of LFA on Maui. More information on this invasive pest is available at http://hawaii.gov/hdoa/pi/ppc/npa-1/npa99-02-lfireant.pdf

Originally from South America, LFA is considered among the world’s worst invasive species. LFA are tiny ants, measuring 1/16th inch long, are pale orange in color. LFA move slowly, unlike the Tropical Fire Ant which is established in Hawai`i, which move quickly and are larger with a larger head in proportion to its body. They can produce painful stings and large red welts and may cause blindness in pets. They can build up very large colonies on the ground and in trees and other vegetation and completely overrun a property. They will also freely move into homes. Any Maui resident who suspect they have Little Fire Ants are encouraged to report it to the state’s Pest Hotline at 643-PEST (7378). This hotline is toll-free on all islands.

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The first detection of LFA in Hawai`i was on the Big Island in 1999. Surveys determined that LFA appeared to have been on the east side for several years prior to their initial detection and was widely distributed in Puna. Attention was then focused on controlling ant populations and preventing the spread to uninfested areas on the island and to other islands.